[Spring] Testing: @SpringBootTest, MockMvc, Testcontainers
spring test, SpringBootTest, WebMvcTest, DataJpaTest, MockMvc, Testcontainers
정의
Spring Boot Test는 단위/슬라이스/통합 테스트 모두 지원. spring-boot-starter-test가 JUnit 5, Mockito, AssertJ, Hamcrest, JsonPath 포함. 슬라이스 어노테이션(@WebMvcTest, @DataJpaTest 등)으로 빠른 부분 테스트.
빠른 시작
testImplementation("org.springframework.boot:spring-boot-starter-test")
testImplementation("org.testcontainers:junit-jupiter")
testImplementation("org.testcontainers:postgresql")@SpringBootTest
class MyApplicationTests {
@Test
void contextLoads() {
// ApplicationContext가 정상 시작되면 통과
}
}@SpringBootTest (통합)
@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
class UserApiIntegrationTest {
@Autowired
private TestRestTemplate restTemplate;
@Test
void shouldCreateUser() {
var dto = new CreateUserDto("alice@example.com", "Alice");
ResponseEntity<User> response = restTemplate.postForEntity("/api/users", dto, User.class);
assertThat(response.getStatusCode()).isEqualTo(HttpStatus.CREATED);
assertThat(response.getBody().email()).isEqualTo("alice@example.com");
}
}RANDOM_PORT로 실제 서버 시작.
@WebMvcTest (web layer만)
@WebMvcTest(UserController.class)
class UserControllerTest {
@Autowired
private MockMvc mockMvc;
@MockBean
private UserService userService;
@Test
void shouldReturnUser() throws Exception {
when(userService.findById(1L)).thenReturn(new User(1L, "alice@example.com", "Alice"));
mockMvc.perform(get("/api/users/1"))
.andExpect(status().isOk())
.andExpect(jsonPath("$.email").value("alice@example.com"));
}
@Test
void shouldReturn404() throws Exception {
when(userService.findById(99L)).thenThrow(new NotFoundException());
mockMvc.perform(get("/api/users/99"))
.andExpect(status().isNotFound());
}
}Controller, JSON 직렬화, validation만 로드. Service/Repository는 mock.
MockMvc
mockMvc.perform(
post("/api/users")
.contentType(MediaType.APPLICATION_JSON)
.content("""
{"email":"a@x.com","name":"Alice"}
""")
.header("Authorization", "Bearer token")
)
.andExpect(status().isCreated())
.andExpect(header().string("Location", containsString("/api/users/")))
.andExpect(jsonPath("$.id").exists())
.andExpect(jsonPath("$.email").value("a@x.com"))
.andDo(print());jsonPath는 응답 본문 검증.
@DataJpaTest (JPA layer)
@DataJpaTest
class UserRepositoryTest {
@Autowired
private UserRepository userRepository;
@Autowired
private TestEntityManager em;
@Test
void shouldFindByEmail() {
em.persistAndFlush(new User("alice@x.com", "Alice"));
Optional<User> found = userRepository.findByEmail("alice@x.com");
assertThat(found).isPresent();
}
}기본은 H2 in-memory. 트랜잭션 자동 rollback. JPA Bean과 Repository만 로드.
실제 DB 사용:
@DataJpaTest
@AutoConfigureTestDatabase(replace = AutoConfigureTestDatabase.Replace.NONE)
class UserRepositoryTest { ... }Testcontainers와 함께 사용.
@JsonTest, @WebFluxTest, @JdbcTest 등
@JsonTest: Jackson 직렬화/역직렬화만@WebFluxTest: WebFlux controller@DataMongoTest,@DataRedisTest: 해당 데이터 layer@RestClientTest: RestTemplate/WebClient mock 서버
Mockito
@Mock
private UserRepository repository;
@InjectMocks
private UserService userService;
@BeforeEach
void setUp() {
MockitoAnnotations.openMocks(this);
}
@Test
void shouldFindById() {
User user = new User(1L, "alice@x.com");
when(repository.findById(1L)).thenReturn(Optional.of(user));
User result = userService.findById(1L);
assertThat(result.email()).isEqualTo("alice@x.com");
verify(repository).findById(1L);
verifyNoMoreInteractions(repository);
}@ExtendWith(MockitoExtension.class)로 자동.
@MockBean / @SpyBean
ApplicationContext의 Bean을 mock으로 교체.
@SpringBootTest
class MyTest {
@MockBean
private EmailService emailService;
@Autowired
private UserService userService;
@Test
void test() {
userService.signUp(...);
verify(emailService).sendWelcome(...);
}
}@MockBean은 새 mock, @SpyBean은 실제 Bean을 wrap.
AssertJ
import static org.assertj.core.api.Assertions.*;
assertThat(user).isNotNull();
assertThat(user.email()).isEqualTo("a@x.com");
assertThat(users).hasSize(3).extracting("email").containsExactly("a", "b", "c");
assertThatThrownBy(() -> userService.delete(99L))
.isInstanceOf(NotFoundException.class)
.hasMessageContaining("not found");Hamcrest보다 read-friendly.
Testcontainers
실제 DB/Redis/Kafka 컨테이너 띄워 통합 테스트.
testImplementation("org.testcontainers:junit-jupiter")
testImplementation("org.testcontainers:postgresql")
testImplementation("org.springframework.boot:spring-boot-testcontainers")@SpringBootTest
@Testcontainers
class UserIntegrationTest {
@Container
static PostgreSQLContainer<?> postgres = new PostgreSQLContainer<>("postgres:16")
.withDatabaseName("test")
.withUsername("test")
.withPassword("test");
@DynamicPropertySource
static void configure(DynamicPropertyRegistry registry) {
registry.add("spring.datasource.url", postgres::getJdbcUrl);
registry.add("spring.datasource.username", postgres::getUsername);
registry.add("spring.datasource.password", postgres::getPassword);
}
@Autowired
private UserRepository userRepository;
@Test
void shouldSaveUser() {
User saved = userRepository.save(new User("a@x.com", "Alice"));
assertThat(saved.id()).isNotNull();
}
}3.1+ @ServiceConnection 더 단순:
@Container
@ServiceConnection
static PostgreSQLContainer<?> postgres = new PostgreSQLContainer<>("postgres:16");자동으로 datasource 연결.
테스트 슬라이스 vs 통합
| @SpringBootTest | @WebMvcTest | @DataJpaTest | |
|---|---|---|---|
| 시작 시간 | 느림 | 빠름 | 중 |
| 로드 범위 | 전체 | controller + jackson | JPA |
| DB | 실제 / mock | mock | H2 / TestContainers |
| 용도 | 통합 시나리오 | controller 단위 | repository 단위 |
빠른 슬라이스 + 적은 수의 통합 = 효율적 테스트 피라미드.
profiles
@SpringBootTest
@ActiveProfiles("test")
class MyTest { ... }application-test.yml이 자동 로드.
TestRestTemplate vs MockMvc vs WebTestClient
| TestRestTemplate | MockMvc | WebTestClient | |
|---|---|---|---|
| 실제 서버 | O | X | O (또는 mock) |
| 빠름 | X | O | 보통 |
| WebFlux | X | X | O |
| 통합 vs 슬라이스 | 통합 | 슬라이스 | 둘 다 |
자주 보는 패턴
@Sql로 데이터 셋업
@Sql("/data/users.sql")
@Test
void test() { ... }
@Sql(scripts = "/data/insert.sql", executionPhase = BEFORE_TEST_METHOD)
@Sql(scripts = "/data/cleanup.sql", executionPhase = AFTER_TEST_METHOD)Page 테스트
@Test
void shouldPaginate() {
userRepository.saveAll(List.of(/* 20명 */));
Page<User> page = userRepository.findAll(PageRequest.of(0, 10, Sort.by("email")));
assertThat(page.getContent()).hasSize(10);
assertThat(page.getTotalElements()).isEqualTo(20);
}WireMock으로 외부 API mock
testImplementation("com.github.tomakehurst:wiremock-standalone:3.0.1")WireMockServer server = new WireMockServer(8089);
server.start();
server.stubFor(get(urlEqualTo("/api/data"))
.willReturn(aResponse().withBody("{\"key\":\"value\"}")));
// test함정
1. @SpringBootTest 남용
전체 컨텍스트 로드는 느림. 슬라이스 우선.
2. @MockBean 사용 시 컨텍스트 캐싱
매번 다른 mock 설정이 컨텍스트를 다시 만들게 함 → 느림.
3. 트랜잭션과 @SpringBootTest
@SpringBootTest는 트랜잭션 자동 X (서비스 자체 트랜잭션). DB 상태 정리 필요.
4. 비동기 테스트
@Test
void asyncCall() {
service.sendAsync();
// 즉시 검증하면 아직 실행 안 됨
await().atMost(5, SECONDS).until(() -> emails.size() == 1); // Awaitility
}5. 직접 ApplicationContext에서 가져오기
@Autowired
private ApplicationContext ctx;
UserService svc = ctx.getBean(UserService.class);테스트에서 정당하지만 production 코드엔 안티패턴.
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